Question

So I have db table>”schools” and a column in this table named “metro”.
In “metro” i have strings like that “Station Name 1, Station Name 2, Station-Name 5”

I’m doing now a search form with select metro stations, so my code look like this:

<select name="categoryID">
<? 

$metro_sql=mysql_query("SELECT metro FROM schools");
while($metro=mysql_fetch_array($metro_sql)){
    $metro_pieces = explode(", ", $metro['metro']);
        foreach (array_unique($metro_pieces, SORT_REGULAR) as $metro_all) {
             echo "<option value=\"".$metro_all."\">".$metro_all."</option>\n  ";
    }
}

And the result:
Metro Station 1
Metro Station 2
Metro Station 3
Metro Station 1
Metro Station 4
Metro Station 5
etc.
What I’m doing wrong?
p.s. sorry for my english.

Answer 1

I would suggest a better database design.

CREATE TABLE school (
  school_id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
  name VARCHAR(255)
);

CREATE TABLE station (
  station_id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
  name VARCHAR(255)
);

CREATE TABLE metro (
  school_id INT NOT NULL,
  station_id INT NOT NULL,
  UNIQUE INDEX (school_id, station_id)
);

You create schools in school and stations in station. When you need to link a school to a station, you add a record to metro. This makes the database normalized.

When you then need to get the stations, you simply do a:

SELECT station.* 
FROM metro
INNER JOIN station
ON metro.station_id = station.station_id
WHERE metro.school_id = $school_id